Thanks for elaborating and the reference to rfc2440 - I now understand where that stray mail (between [RFC2822] and name-addr) in rfc4880 comes from...
Anyway, I'll treat it as if it says RFC 2822 mailbox and will treat angle brackets with bare addresses as optional.

Anyway, thanks for fixing this.

It does work indeed!

Not sure if that is the complete fix - if you do something like:

with gpg.Context(...) as context:
    ...
... cause an exception after the context has been closed ...

then context will still be a valid reference to the gpg.Context instance, and may cause segfaults when something tries to access things inside it (f.e. for serialisation).
I like your previous solution with the accessor checks, because that actually fixes the issue.
Stylistically, maybe __del__ should just be renamed to cleanup or free, and then make sure to call that function from both __exit__ and __del__.

Can confirm, we've been running into this as well, but never filed a bug report. Our solution is to have this in our codebase:

Not exactly the answer I was hoping for..